From 77bb0d5f5047223e5d8f855ee21442ea9505834e Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Fri, 27 Oct 2023 22:56:12 +0200
Subject: [PATCH] gh-108765: Include explicitly <unistd.h> in signalmodule.c
 (#111402)

unistd.h is needed by alarm() and pause() functions.
---
 Doc/whatsnew/3.13.rst  | 3 ++-
 Modules/signalmodule.c | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/Doc/whatsnew/3.13.rst b/Doc/whatsnew/3.13.rst
index 34dd3ea8858ea2..84d5daae6e623c 100644
--- a/Doc/whatsnew/3.13.rst
+++ b/Doc/whatsnew/3.13.rst
@@ -1120,7 +1120,8 @@ Porting to Python 3.13
 * ``Python.h`` no longer includes the ``<unistd.h>`` standard header file. If
   needed, it should now be included explicitly. For example, it provides the
   functions: ``read()``, ``write()``, ``close()``, ``isatty()``, ``lseek()``,
-  ``getpid()``, ``getcwd()``, ``sysconf()`` and ``getpagesize()``.
+  ``getpid()``, ``getcwd()``, ``sysconf()``, ``getpagesize()``, ``alarm()`` and
+  ``pause()``.
   As a consequence, ``_POSIX_SEMAPHORES`` and ``_POSIX_THREADS`` macros are no
   longer defined by ``Python.h``. The ``HAVE_UNISTD_H`` and ``HAVE_PTHREAD_H``
   macros defined by ``Python.h`` can be used to decide if ``<unistd.h>`` and
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index 2932d94858afde..f3ba0915760f5e 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -21,6 +21,9 @@
 #  include "socketmodule.h"       // SOCKET_T
 #endif
 
+#ifdef HAVE_UNISTD_H
+#  include <unistd.h>             // alarm()
+#endif
 #ifdef MS_WINDOWS
 #  ifdef HAVE_PROCESS_H
 #    include <process.h>